Method of electrostatic separation.



No. 327,115. v PATENTED JULY 311-1506.

G.. W. BIOK'ARD. METHOD OF ELECTROSTATIC SEPARATION.

APPLIOATION FILED 8121227, 1905. y

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'- UNITED 'sirArEs PATENT OFFICE. -GR-EENLEAF VVHITTIER PICKARD, OF ABIESBURY, MASSACHUSETTS,

ASSIGNOR, BY MESNE ASSIGNMENTS, TO-HUFF ELECTROSTATIC SEPARATOR COMPANY, A CORPORATION OF MAINE.

METHOD OF ELECTROSTATIC SEPARATlON-' To all whom it may concern: Be it known that I, GREENLEAF WHrr'rIER PIOKARD, a citizen of the United States,and a resident of Amesbury, in the county of Es sex and State of Massachusetts, have invented new and useful Improvements in Methods of Electrostatic Separation, of which the following is a specification.

My invention relates to the art of electrostatic separation or concentration of mixed comminuted materials; and it consists of improvements in the method of electrostatic separation whereby the separator is given increasedefficiency and is enabled to operate successfully over a much larger range of ma terials than heretofore.

In order to a full understanding of my improved method, I here describe an ap aratus, shown in the annexed drawings, by w 'ch my improved method may efiectively be carried out. In an application for patent filed concurrently herewith, Serial No. 280,323, filed September 27, 1905, haveclaimedthis apparatus and its structural combinations.

In thedrawings hereto annexed, Figure 1 is a vertical cross-section of an apparatus by which m method is carried out. Fig.2 is a vertical ongitudinal section ofia portion of I 1 the hopper for feeding material, and-Fig. 3 is a detail showing in longitudinal section one of the-electrodes of the apparatus.

The, separating devices consist'of a vertically-arranged series ofcylindrical metallic electrodes E, mounted upon bearings to ro-. tate in the direction indicated by the arrows. These electrodes areconnected, as shown conventionally, with one terminus of an exciting-machine, these Wires being shown'as' X X. The opposed electrodes E are arranged in series, there being a plurality of such op'.

posed electrodes for each of the main cylin-' Specification of Letters Patent, Application filed September 27, 1905; Serial No. 280,322,-

the opposite end serves to conduct the hot trodes E are mounted. on

C. Upon the Patented. July 31, 1906.-

nal heating-chambers H and H3, the latter extendmg fromend to end inside the hopper, so that the material must pass on either side of the, heating-chamber H and next to the chamber H on one side and H on the other. Near the bottom of this hopper there is mounted the agitator A, which, as shown in Fig. 2, is operated by a crank and connecting-rod and serves to scrape and sift the comminuted material through the slot C, so that it will fall in a regular stream u on the surface of the upper electrode E. pon the end of the hopper I-I there is formed the chamber H and upon the 0p osite end a similar chamber I-I isprovide d. A pipe H serves to conduct heated gases, such assteamor hot air, into the chambers H H H so that the material falling through the ho per II will become thoroughl and effective heated in its passage over t e surfaces of t e heating chambers. A vent H at thechamber H at gases away to any desired point. =The elecearings e in the ends of the chamber 0, and tubular trunnions 5 secured .to the electrodes E, serve to carrythe electrodes and also as openings wherethrough to induct heated gases to the interior ofthe electrodes E. Nozzles e are pro-b vided for this purpose. The bearings for the electrodes are shown at e. At the o posite end the hollow trunnions e serve to al ow the gases to escape from inside the electrode.

It has been recognized from the initiation of the art ofelectrostatic separation that the processes are assisted materially by presenting the substances to be treated in a perthe'practice for a long time to heat materials before they are fed to the electrodes of an 'electrostatlc separator, this heating serving to facilitate the separationof many materials. I have discovered, however, that if a heated atmosphere be maintained also near and around the electrodes themselves, especially if the electrodes themselves are heated 100 face of the electrodes, the resulting 'separaso that the atmosphere is hottest at the surtions are far more thorough than under any other condition observed by me, and, moreover, many mixtures of material which, as far as I am aware, have heretofore res1sted 105 efiectual separation by the electrostatic,

fectly dry state, and consequently it has been 30 as B.

method are by this improvement completely and easily separated.

The value of the plurality of electrodes E resides in their successful operation upon the material as it passes over or along the surface of the larger electrode l There is a concentration of field in close proximity to each one of the smaller electrodes, and while the great bulk of separation apparently takes place [0 when the material is passing between the electrode E and the first of the smaller electrodes e nevertheless separation continues thereafter, the successive small electrodes searching out the conductive particles from 15. the mass and gleaning, as itwere, after the separation effected at the first opposed electrode. If the desired separation cannot be completed by a single set of electrodes E E, the material which has not been repelled 2o frolnthe upper electrode E is conducted b the sloping side of the divider D to a secon electrode E, and so on, the electrical conditions at all the electrodes usually being preferably the same, the electrodes [*1 being con- 2 5 nected to one terminus of the exciting appamight be carried around through a complete rotation of the electrode. vide rubbers or scrapers S S to clean the electrodes E at the bottom and top thereof, respectively. For simplicity of construction the rubbers S may be pivotally attached to the rubbers S, the latter-being limselyguided, as by pins S set into the ends of the easing C, a spring S, attached to the rubber S, serving to hold both into contact with their respective electrodes.

The exciting apparatus which I prefer to employ in connection with this separator is such a one as described in the Letters Patent of the United States No. 796,011, dated August 1, 1905.

What I claim, and desire to secure by Letters Patent, is

1. The method of electrostatic sepzn'ation, which consists in heating the mixture to be separated, and thereafter subjecting it to electrostatic separative influence in a heated atmosphere and thereafter separately collecting the materials.

2. The method of electrostatic separation, which consists in heating the mixture to be separated, thereafter passing the. nuiterial to an electrode, and heating the electrode and thereafter separately collecting the materials.

Signed by me at Boston, Massaclmsetts,

this 23d day of September, 1905.

' (lREllN liEAF Wlll'lTllllt llCKAltl). Witnesses:

ODIN RoBEnTs,

J OSEPII T. BRENNAN.

lhercfore 1 pro-- 

